Syncing inventory is not copying one number everywhere. Shopify, Amazon, Walmart, Faire, and other channels represent availability differently, so the first decision is which count is authoritative and how much stock each channel may sell. Then define the write and review rules before automating updates.
Stock is an inventory level at a location: available, on hand, committed, and other states you name. A product's total is not that location count.
Merchant-fulfilled quantity is fulfillment availability on the listing. FBA inventory is a summary Amazon holds. You do not pick an arbitrary fulfillment center.
Quantity is at a ship node. WFS units represent inventory Walmart is holding rather than stock the seller can set.
Faire returns on-hand, committed, and available, and the brand can write on-hand and available. Etsy quantity for a variation is on the offering, and there is no shop-wide inventory call. eBay quantity is on the inventory item. WooCommerce has one stock quantity and no warehouse on that field. TikTok Shop stock can be read per warehouse.
A Faire order and a Shopify order can both sell the same units before either side is updated. The APIs will accept both writes. The fix is one source quantity, then a write to the other side, not a setting inside Faire that copies Amazon.
Review the inventory information available from each channel. Agree on source and allocation rules instead of treating different stock fields as interchangeable.
Available stock actions differ by integration and account. Confirm which updates are supported and which should be reviewed before making channel changes.
Define how your team handles stock differences, low availability, and replenishment decisions. Channel-specific rules and the reorder line remain part of your operating process.
Read merchant-fulfilled quantity, or the FBA summary, from Amazon, and write the quantity you trust to the Shopify inventory level at a location. They are different fields. A sync has to name which one wins.
Each keeps its own quantity. A Faire order does not, by itself, reduce the Shopify location. Someone, or a system, has to write the other side.
No. Walmart quantity is at a ship node. FBA inventory is a separate Amazon read. WFS inventory represents units Walmart holds rather than stock the seller can set.
No. Each marketplace has its own integration and inventory rules. A workflow may coordinate several updates when those connections support them; a single platform call does not update every marketplace.
Whether an inventory update can be made depends on the supported channel actions and account access. Your team can define review steps for any change before it is put into an active workflow.
Updated 30 September 2026.
The grants, before the quantities.
When a separate inventory system is the source quantity.
Connect company data and put AI to work in supported workflows.
Bring the SKU that disagrees across channels.
Bring a SKU with different counts in two places. We will trace the source, the allocation rule, and the updates that should follow.
Free assessment →